Internal combustion engines are known to produce combustion byproducts that are abated by so-called after-treatment systems associated with the engine. Such after-treatment systems typically include one or more catalysts arranged on substrates, which are packed into enclosures and placed along a flow path of exhaust gases from the engine so they can treat and abate substances in the exhaust gas that are undesirable for release into the atmosphere.
In a typical installation, catalysts deposited on substrates, for example, ceramic substrates, are enclosed into a metal container, which is placed in the exhaust conduit of an engine. For achieving a proper fit, providing cushioning, and avoiding leakage of gases past the substrates, a mat is placed around the substrates. The mat, which may be made from ceramic fibers and is compressible, is placed between the substrates and the inner surface of the can when the can is assembled. Typically, during assembly, a considerable amount of customization is required to properly assemble the substrates into the can because there is wide tolerance and size variation of the substrates, especially square substrates. The customization includes custom cutting of the retention mats to meet the required space claims. The customization results in slow assembly and challenges in precut inventory since the mat size will not be known until assembly starts.
In the past, various solutions have been proposed to address the time consuming aspect of the required customizations. One example of a previously proposed solution can be seen in PCT Application Publication No. WO 2016/036802 A1, which published on Mar. 10, 2016 to Rochaz et al. (“Rochaz”). Rochaz describes a mounting mat for holding a substrate into a can. The mounting mat is sized to wrap around three lateral sides of a substrate such that, when four substrates are assembled together in a bundle, the bare side of each substrate is oriented to contact a matted side of an adjacent substrate so that all four substrates have a matted surface on all four lateral sides. While the solution proposed in Rochaz is effective in assembling a mat around substrates, it still does not address the issue of customization during assembly in that excess mounting mat material will still need to be manually removed from the edges of the mat to avoid overlap of adjacent mats when the bundle is put together.